AwesomePlayer::onVideoEvent除了透過OMXCodec::read取得解碼後的資料外，還必須將這些資料
(mVideoBuffer)傳給video renderer，以便畫到螢幕上去。
(1)
要將mVideoBuffer中的資料畫出來之前，必須先建立mVideoRenderer
void AwesomePlayer::onVideoEvent()
{
...
if (mVideoRenderer == NULL)
{
initRenderer_l();
}
...
}
void
AwesomePlayer::initRenderer_l()
{
if (!strncmp("OMX.",
component, 4))
{
mVideoRenderer = new AwesomeRemoteRenderer(
mClient.interface()->createRenderer(
mISurface,
component,
...));
.......... (2)
}
else
{
mVideoRenderer = new AwesomeLocalRenderer(
...,
component,
mISurface);
............................ (3)
}
}
(2)
如果video decoder是OMX component，則建立一個AwesomeRemoteRenderer作為mVideoRenderer
從
上段的程式碼(1)來看，AwesomeRemoteRenderer的本質是由OMX::createRenderer所創建的。
createRenderer會先建立一個hardware renderer -- SharedVideoRenderer
(libstagefrighthw.so)；若失敗，則建立software renderer -- SoftwareRenderer
(surface)。
sp<IOMXRenderer>
OMX::createRenderer(...)
{
VideoRenderer *impl = NULL;
libHandle = dlopen("libstagefrighthw.so", RTLD_NOW);
if
(libHandle)
{
CreateRendererFunc func = dlsym(libHandle,
...);
impl = (*func)(...); <----------------- Hardware
Renderer
}
if (!impl)
{
impl = new
SoftwareRenderer(...); <---- Software Renderer
}
}
(3) 如果video decoder是software
component，則建立一個AwesomeLocalRenderer作為mVideoRenderer
AwesomeLocalRenderer
的constructor會呼叫本身的init函式，其所做的事和OMX::createRenderer一模一樣。
void AwesomeLocalRenderer::init(...)
{
mLibHandle = dlopen("libstagefrighthw.so", RTLD_NOW);
if
(mLibHandle)
{
CreateRendererFunc func = dlsym(...);
mTarget = (*func)(...); <---------------- Hardware Renderer
}
if (mTarget == NULL)
{
mTarget = new SoftwareRenderer(...);
<--- Software Renderer
}
}
(4)
mVideoRenderer一經建立就可以開始將解碼後的資料傳給它
void AwesomePlayer::onVideoEvent()
{
if
(!mVideoBuffer)
{
mVideoSource->read(&mVideoBuffer,
...);
}
[Check Timestamp]
if
(mVideoRenderer == NULL)
{
initRenderer_l();
}
mVideoRenderer->render(mVideoBuffer);
<----- Render Data
}